1. Technical Field
The present disclosure relates to a media conveyance device that conveys continuous media delivered from a paper roll, and a drive motor for rotating the paper roll. The invention also relates to a printer having the media conveyance device, and a control method of the printer.
2. Related Art
Printers having a conveyance mechanism that conveys continuous recording paper delivered from a paper roll through a conveyance path past the printing position of a printhead, and a drive motor that rotates the paper roll, are known from the literature. To prevent the tension on the recording paper from fluctuating greatly when recording paper conveyance starts and the conveyance speed becoming unstable in such printers, an initialization step is performed to remove the slack in the recording paper before conveyance starts. In the initialization operation the printer drives the drive motor to rotate the paper roll and take up slack in the recording paper between the conveyance mechanism and the paper roll onto the paper roll.
A rewind device that rewinds recording paper onto a paper roll is described in JP-A-2006-150859. This rewind device includes a drive motor that turns the paper roll; a tension roller that is located between the conveyance mechanism of the printer and the paper roll, and moves between highest and lowest positions tracking change in the tension on the recording paper; a tension spring that urges the tension roller to the lowest position; a sensor that detects the current position of the tension roller; and a rewinding control unit that controls the drive motor based on the current position of the tension roller.
If a configuration equivalent to the mechanism of the rewind device described in JP-A-2006-150859 is included in a printer, the initialization operation that removes slack in the recording paper can be executed by controlling driving the drive motor based on the current position of a movable member (tension roller). By controlling driving the drive motor based on the current position of the movable member to rewind or deliver recording paper during conveyance of the recording paper by the conveyance mechanism, this configuration can suppress fluctuation in the tension (back tension) on the recording paper and can suppress a drop in print quality due to variation in the conveyance speed.
However, problems such as described below occur in the initialization operation when a configuration corresponding to the mechanism described in JP-A-2006-150859 is deployed in a printer.
When there is slack in the recording paper between the conveyance mechanism and the paper roll, there is no tension on the recording paper and the movable member is positioned to a first position at one end of its range of movement, and in this position there is no way to know how much slack is in the recording paper based on the current position of the movable member.
Therefore, when there is minimal slack in the recording paper when operation starts, the recording paper may be rewound excessively onto the paper roll by driving the drive motor, and excessive tension may be applied to the recording paper. As a result, the recording paper may be pulled out of the conveyance mechanism to the paper roll side, resulting in the conveyance mechanism being unable to convey the recording paper.
When the recording paper is rewound too much on the paper roll by driving the drive motor, the movable member moves abruptly to a second position, which is the opposite end of the range of movable member movement as the first position end, and collides with the stop that limits the range of movable member movement on the second position side. This produces noise, including the sound of impact.
To resolve these problems, driving the drive motor in a low output operating mode is conceivable. For example, excessively rewinding the recording paper onto the paper roll can be prevented even when the drive motor is driven when there is little slack by driving the drive motor in an operating mode with output low enough that the movable member cannot reach the second position by the urging force of the urging member.
However, when the drive motor is driven in a low output operating mode, the operation that checks movement of the movable member cannot be executed. More specifically, the initialization operation must confirm that the movable member can move between the first position and the second position to ensure that tension can be controlled normally when controlling driving the drive motor based on the current position of the movable member to suppress fluctuation in the tension on the recording paper during recording paper conveyance. However, because the movable member cannot be moved to the second position in resistance to the urging force of the urging member when the drive motor is driven in a low output operating mode, movement of the movable member cannot be confirmed.